Considering Corrosion Allowance in flange thickness 2

[Amr Shams]

A closed drain drum having a 2" nozzle with blind flange RF.
Should I use the UG-34 calculations and include the corrosion allowance of the vessel to the flange thickness? or use the typical standard blind flange with a suitable rating without considering corrosion allowance?
we already purchased the standard flanges without considering C.A. But the AI said that All permanent blinds shall be designed in corroded condition.
If adding the corrosion allowance is mandatory what are our options to solve this issue?

 

[saplanti]

GD2 is correct in his statement. However it becomes a special flange, you cannot call it standard flange in the drawing any more. Think about replacement.

Another way might be the required wall thickness calculation to the code, and add the CA.